Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual é o número médio para Black Milk?
 ###Tabelas: CREATE TABLE top_50_quarterbacks_in_nfl_history (top_50_quarterbacks_in_nfl_history_id AUTO_INCREMENT PRIMARY KEY, Rank INT, Quarterback VARCHAR, Seasons VARCHAR, Teams VARCHAR, Team Wins INT, Team Losses INT, Career Wins INT, Career Losses INT, Ties INT) CREATE TABLE previous_championship_encounters (previous_championship_encounters_id AUTO_INCREMENT PRIMARY KEY, Year INT, Venue VARCHAR, Competition VARCHAR, Kilkenny score VARCHAR, Waterford score VARCHAR) CREATE TABLE residents_of_white_deer_park (residents_of_white_deer_park_id AUTO_INCREMENT PRIMARY KEY, Animal Name VARCHAR, Species VARCHAR, Books VARCHAR, TV Series VARCHAR, Gender VARCHAR, TV Seasons VARCHAR, Mate VARCHAR, First Appearance VARCHAR, Last Appearance VARCHAR) CREATE TABLE 5001–5100 (5001–5100_id AUTO_INCREMENT PRIMARY KEY, NGC number INT, Object type VARCHAR, Constellation VARCHAR, Right ascension ( J2000 ) VARCHAR, Declination ( J2000 ) VARCHAR, Apparent magnitude INT) CREATE TABLE highest_critically_reviewed_albums_metacritic (highest_critically_reviewed_albums_metacritic_id AUTO_INCREMENT PRIMARY KEY, Number INT, Artist VARCHAR, Album VARCHAR, Average score INT, Number of reviews VARCHAR)  
SELECT AVG Number FROM highest_critically_reviewed_albums_metacritic WHERE Artist = black milk